﻿namespace 四
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello, World!");
        }
    }
    class Circle
    {
        Circle() { r = 1; }
        Circle(int x)
        {
            r = x;
        }
        private double r;
        public double getArea()
        {
            return r * r * 3.14;
        }
        public double getRadius()
        {
            return 2 * r * 3.14;
        }
    }
}
